Methods of making intermediates from polyhydroxyalkanoates

ABSTRACT

Methods of forming intermediates from PHAs are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority under 35 U.S.C. §119(e)(1) toU.S. Provisional Patent Application Serial No. 60/341,546, filed Dec.18, 2001, and entitled “Process of Making Chemical Intermediates fromNaturally Occurring Polyhydroxyalkanoates,” and to U.S. ProvisionalPatent Application Serial No. 60/402,469, filed Aug. 9, 2002, andentitled “Alkanoic and Alkenoic Acid Esters and Methods of Making Same,”both of which are incorporated by reference.

TECHNICAL FIELD

[0002] The invention generally relates to methods of makingintermediates from polyhydroxyalkanoates (PHAs).

BACKGROUND

[0003] Various chemical intermediates, such as esters, amides, diols andacids, are known to be useful. For example, certain chemicalintermediates can be used as solvents (e.g., coalescing solvents,cleaning solvents), process additives, plasticizers, surface activeagents, in the formulation of products (e.g., industrial products,consumer products), and/or monomers in a polymerization process.

[0004] SUMMARY

[0005] The invention generally relates to methods of makingintermediates from PHAs.

[0006] In one aspect, the invention features a method. The methodincludes treating a biomass containing a PHA to form a PHA intermediate,and removing at least about 10 weight percent of the PHA intermediatefrom the biomass.

[0007] In another aspect, the invention features a method that includescontacting a PHA with an aprotic catalyst to form an ester. The esterhas only one monomer unit from the PHA.

[0008] In a further aspect, the invention features a method thatincludes treating a PHA-containing non-lyophilized biomass to form anester, and removing at least some of the ester from the biomass.

[0009] In one aspect, the invention features a method that includescombining a PHA with an alcohol to form an ester. The PHA and thealcohol form a combination containing less than about one milliliter ofsolvent other than the alcohol per gram of PHA.

[0010] In another aspect, the invention features a method that includescombining a PHA and an alcohol to form an ester from a PHA. The percentyield of the ester is at least about 50%, and a ratio of the moles ofthe alcohol per mole of PHA monomer unit is less than about 20.

[0011] In a further aspect, the invention features a method thatincludes heating a PHA to a temperature of at least about 180° C. toform an ester.

[0012] In one aspect, the invention features a method that includestreating a PHA to form an amide. The amide has only one repeat unit fromthe PHA.

[0013] In another aspect, the invention features a method that includestreating a biomass containing a PHA to form an amide.

[0014] In a further aspect, the invention features a method thatincludes heating a PHA to a temperature of at most about 90° C. to forman amide. The percent yield of the amide is at least about 50%.

[0015] In one aspect, the invention features a method that includesheating a PHA to form a cyclic amide.

[0016] In another aspect, the invention features a method that includeshydrogenolyzing a PHA to form a diol.

[0017] In one aspect, the invention features a method that includesheating a biomass containing a PHA to form an alkenoic acid. The percentyield of alkenoic acid from the PHA is at least about 50%.

[0018] In another aspect, the invention features a method that includesheating a PHA to a temperature of at least about 200° C. to form analkenoic acid.

[0019] In a further aspect, the invention features a method thatincludes treating a PHA to form acrylic acid. The PHA has at least one3-hydroxypropionate monomer.

[0020] In one aspect, the invention features a method. The methodincludes heating a mixture containing a first portion of a PHA to form afirst portion of an alkenoic acid, and adding, after forming the firstportion of the alkenoic acid, a second portion of the PHA to themixture.

[0021] The methods can further include using the intermediate(s) (e.g.,as a solvent, as a process additive, as a monomer to form a polymer,and/or in the formulation of a product).

[0022] In certain embodiments, the methods can be relatively nontoxic,relatively environmentally friendly, relatively sustainable, relativelysimple and/or relatively inexpensive.

[0023] In some embodiments, the intermediates can be formed atrelatively high yield.

[0024] In certain embodiments, the methods can result in the formationof a chiral intermediate. This can be advantageous, for example, if theusefulness (e.g., commercial usefulness) of the intermediate depends onthe chirality of the intermediate.

[0025] In some embodiments, the PHAs can serve as non-fossil carbonbased feedstocks for materials (PHA intermediates).

[0026] Features, aspects and advantages of the invention are in thedescription and claims.

DETAILED DESCRIPTION

[0027] In general, the methods include treating a PHA to form a PHAintermediate. The methods optionally include using the PHA intermediate(e.g., as a solvent, as a process additive, as a monomer to form apolymer, a precursor to form another product, and/or in the formulationof a product).

[0028] A PHA contains multiple monomer units. Typically, a PHA containsat least about 500 monomer units (e.g., at least about 1,000 monomerunits). In some embodiments, when a PHA is a homopolymer, the multiplemonomer units contained in the PHA are all the same. In certainembodiments, when the PHA is a copolymer, the multiple monomer unitscontained in the PHA include at least two different monomer units.

[0029] A PHA intermediate is a compound that has fewer monomer unitsthan present in the PHA from which the PHA intermediate was formed. Insome embodiments, a PHA intermediate contains only one monomer unit fromthe PHA. In certain embodiments, a PHA intermediate can contain multiplemonomer units (e.g., from two monomer units to 500 monomer units, fromtwo monomer units to 400 monomer units, from two monomer units to 300monomer units, from two monomer units to 200 monomer units, from twomonomer units to 100 monomer units, from two monomer units to 50 monomerunits, from two monomer units to 40 monomer units, from two monomerunits to 25 monomer units), but the PHA intermediate contains fewermonomer units than present in the PHA itself. Examples of PHAintermediates include esters, amides, diols and acids.

[0030] As explained below, treating a PHA to form a PHA intermediategenerally includes heating the PHA under appropriate conditions (e.g.,in the presence of a reactant, in the presence of a solvent, in thepresence of a catalyst, and/or at elevated pressure).

[0031] In some embodiments, the methods result in a relatively highyield of the PHA intermediate. For example, the percent yield of PHAintermediate from the PHA can be at least about 30% (e.g., at leastabout 35%, at least about 40%, at least about 45%, at least about 50%,at least about 55%, at least about 60%, at least about 65%, at leastabout 70%, at least about 75%, at least about 80%, at least about 85%,at least about 90%, at least about 95%, at least about 98%). The percentyield of a PHA intermediate from a PHA is determined as follows. Thenumber of moles of the PHA intermediate is multiplied by the number ofmonomer units per mole of the PHA intermediate, which provides a valueA. The number of moles of PHA is multiplied by the number of monomerunits per mole of PHA, which provides a value B. The value A is dividedby the value B to provide a value C, which is multiplied by 100%.

[0032] In embodiments in which a chiral PHA is treated to form a chiralPHA intermediate, the percent chirality yield of the chiral PHAintermediate can be relatively high. For example, the percent chiralityyield of a chiral PHA intermediate from a chiral PHA can be at leastabout five percent (e.g., at least about 10%, at least about 25%, atleast about 50%, at least about 75%, at least about 85%, at least about90%, at least about 95%, at least about 98%). The percent chiralityyield of a chiral PHA intermediate from a chiral PHA is determined asfollows. The number of moles of the chiral PHA intermediate ismultiplied by the number of chiral monomer units per mole of the chiralPHA intermediate, which provides a value D. The number of moles ofchiral PHA is multiplied by the number of chiral monomer units per moleof the chiral PHA, which provides a value E. The value D is divided bythe value E to provide a value F, which is multiplied by 100%.

[0033] As used herein, the term chiral PHA refers to a PHA in which atleast some of the monomer units are chiral, and all the chiral monomerunits in the PHA have the same chirality (e.g., R configuration or Sconfiguration). As used herein, the term chiral PHA intermediate refersto a PHA intermediate that is formed from a chiral PHA and that has thesame chirality as the chiral monomer units in the chiral PHA.

[0034] In certain embodiments in which the PHA is derived from biomassand at least some of the PHA is not removed from the biomass beforebeing treated to form the PHA intermediate, the methods can includeremoving at least a portion of the PHA intermediate from the biomass.For example, at least about 10 weight percent (e.g., at least about 20weight percent, at least about 30 weight percent, at least about 40weight percent, at least about 50 weight percent, at least about 60weight percent, at least about 70 weight percent, at least about 80weight percent, at least about 90 weight percent, at least about 95weight percent, at least about 98 weight percent) of the PHAintermediate can be removed from the biomass.

[0035] PHAs

[0036] In certain embodiments, a PHA has at least one monomer unit withthe structure:

[0037] n is zero or an integer (e.g., one, two , three, four, five, six,seven, eight, nine, 10, 11, 12, 13, 14, 15, etc.). Each of R₁, R₂, R₃,R₄, R₅ and R₆ is independently a hydrogen atom, a halogen atom or ahydrocarbon radical. A hydrocarbon radical contains at least one carbonatom (e.g., one carbon atom, two carbon atoms, three carbon atoms, fourcarbon atoms, five carbon atoms, six carbon atoms, seven carbon atoms,eight carbon atoms, etc.). A hydrocarbon radical can be saturated orunsaturated, substituted or unsubstituted, branched or straight chained,and/or cyclic or acyclic. Examples of substituted hydrocarbon radicalsinclude halo-substituted hydrocarbon radicals, hydroxy-substitutedhydrocarbon radicals, nitrogen-substituted hydrocarbon radicals andoxygen-substituted hydrocarbon radicals. Examples of hydrocarbonradicals include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl anddecyl.

[0038] Examples of monomer units include 3-hydroxybutyrate,3-hydroxypropionate, 3-hydroxyvalerate, 3-hydroxyhexanoate,3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynonaoate,3-hydroxydecanoate, 3-hydroxydodecanoate, 3-hydroxytetradecanoate,3-hydroxyhexadecanoate, 3-hydroxyoctadecanoate, 4-hydroxybutyrate,4-hydroxyvalerate, 5-hydroxyvalerate, and 6-hydroxyhexanoate.

[0039] In some embodiments, a PHA can be a homopolymer (all monomerunits are the same). Examples of PHA homopolymers include poly3-hydroxyalkanoates (e.g., poly 3-hydroxypropionate, poly3-hydroxybutyrate, poly 3-hydroxyhexanoate, poly 3-hydroxyheptanoate,poly 3-hydroxyoctanoate, poly 3-hydroxydecanoate, poly3-hydroxydodecanoate), poly 4-hydroxyalkanoates (e.g., poly4-hydroxybutyrate), poly 5-hydroxyalkanoates (e.g., poly5-hydroxypentanoate), poly 6-hydroxyalkanoates (e.g., poly6-hydroxyhexanoate) and polylactic acid. Another example of ahomopolymer of interest is polyglycolic acid (for which there is onlyone carbon other than the carbonyl carbon in the monomer structure).

[0040] In certain embodiments, a PHA can be a copolymer (contain two ormore different monomer units). Examples of PHA copolymers include poly3-hydroxybutyrate-co-3-hydroxypropionate, poly3-hydroxybutyrate-co-3-hydroxyvalerate, poly3-hydroxybutyrate-co-3-hydroxyhexanoate, poly3-hydroxybutyrate-co-4-hydroxybutyrate, poly3-hydroxybutyrate-co-4-hydroxyvalerate, poly3-hydroxybutyrate-co-6-hydroxyhexanoate, poly3-hydroxybutyrate-co-3-hydroxyheptanoate, poly3-hydroxybutyrate-co-3-hydroxyoctanoate, poly3-hydroxybutyrate-co-3-hydroxydecanoate, poly3-hydroxybutyrate-co-3-hydroxydodecanotate, poly3-hydroxybutyrate-co-3-hydroxyoctanoate-co-3-hydroxydecanoate, poly3-hydroxydecanoate-co-3-hydroxyoctanoate, and poly3-hydroxybutyrate-co-3-hydroxyoctadecanoate. Although examples of PHAcopolymers having two different monomer units have been provided, a PHAcan have more than two different monomer units (e.g., three differentmonomer units, four different monomer units, five different monomerunits, six different monomer units, seven different monomer units, eightdifferent monomer units, nine different monomer units, etc.).

[0041] In certain embodiments, the PHA is derived from biomass, such asplant biomass and/or microbial biomass (e.g., bacterial biomass, yeastbiomass, fungal biomass). Biomass-derived PHA can be formed, forexample, via enzymatic polymerization of the monomer units. Typically,the biomass is non-lyophilized. The biomass can be formed of one or moreof a variety of entities. Such entities include, for example, microbialstrains for producing PHAs (e.g., Alcaligenes eutrophus (renamed asRalstonia eutropha), Alcaligenes latus, Azotobacter, Aeromonas,Comamonas, Pseudomonads), genetically engineered organisms, preferablycontaining no recombinant plasmids, for producing PHAs (e.g.,Pseudomonas, Ralstonia, Escherichia coli, Klebsiella), yeasts forproducing PHAs, and plant systems for producing PHAs. Such entities aredisclosed, for example, in Lee, Biotechnology & Bioengineering 49:1-14(1996); Braunegg et al., (1998), J. Biotechnology 65: 127-161; Madison,L. L. and Huisman, G. W. (1999), Metabolic Engineering ofPoly(3-Hydroxyalkanoates): From DNA to Plastic. Microbiol. Mol. Biol.Rev. 63, 21-53; and Snell and Peoples 2002, Metabolic Engineering 4:29-40, which are hereby incorporated by reference.

[0042] In some embodiments in which the PHA is derived from biomass,most of the PHA that is treated to form the PHA intermediate is notremoved from the biomass before being treated to form the intermediate.For example, in certain embodiments, less than about 50 weight percent(e.g., less than about 40 weight percent, less than about 30 weightpercent, less than about 20 weight percent, less than about 10 weightpercent, less than about weight percent five weight percent, less thanabout three weight percent, less than about one weight percent, aboutzero weight percent) of the PHA that is treated to form the PHAintermediate is removed from the biomass before being treated to formthe PHA intermediate.

[0043] In certain embodiments in which the PHA is derived from biomass,most of the PHA that is treated to form the PHA intermediate is removedfrom the biomass before being treated to form the PHA intermediate. Forexample, in some embodiments, at least about 60 weight percent (at leastabout 70 weight percent, at least about 80 weight percent, at leastabout 90 weight percent, at least about 95 weight percent, at leastabout 98 weight percent, about 100 weight percent ) of the PHA that istreated to form the PHA intermediate is removed from the biomass beforebeing treated to form the PHA intermediate.

[0044] Esters

[0045] Treating a PHA to form an ester (e.g., an alkanoic acid ester, analkenoic acid ester) generally includes combining the PHA with analcohol (e.g., a monohydric alcohol, a polyhydric alcohol) andoptionally a catalyst (e.g., a protic catalyst, an aprotic catalyst),and exposing the PHA to elevated temperature and/or elevated pressure.

[0046] The alcohol can be represented by the structure R₇OH, where R₇ isa hydrocarbon radical that contains one or more carbon atoms (e.g., onecarbon atom, two carbon atoms, three carbon atoms, four carbon atoms,five carbon atoms, six carbon atoms, seven carbon atoms, eight carbonatoms, etc.). R₇ can be saturated or unsaturated, substituted orunsubstituted, branched or straight chained, and/or cyclic or acyclic.Examples of substituted hydrocarbon radicals include halo-substitutedhydrocarbon radicals, hydroxy-substituted hydrocarbon radicals,nitrogen-substituted hydrocarbon radicals and oxygen-substitutedhydrocarbon radicals. Examples of hydrocarbon radicals include methyl,ethyl, propyl, butyl, 2-ethylhexyl, isopropyl, isobutyl, tertiary butyl,hexyl, octyl, cyclohexyl, decyl, dodecyl, stearyl, oleyl, linolyl andlinolenyl.

[0047] Examples of alcohols include methanol, ethanol, propanol,butanol, 2-ethylhexanol, cyclohexanol, decyl alcohol, dodecyl alcohol,isopropyl alcohol, isobutyl alcohol, dodecyl alcohol, stearyl alcohol,oleyl alcohol, linolyl alcohol, linolenyl alcohol, propylene glycol,glycerol, ethylene glycol, propylene glycol, 1,2-propane diol,1,3-propane diol, 1,3-butane diol, 1,4-butane diol, 1,6-hexane diol,glycerol, erythritol, pentaerythritol, dipentaerythritol, thrimethylolpropane, xylose, sucrose, dextrose and triethanolamine.

[0048] In certain embodiments, an ester formed by treating the PHA is analkanoic acid ester. In some embodiments, an alkenoic acid ester can berepresented by the structure:

[0049] y is less than the number of monomer repeat units in the PHA. Insome embodiments, y is from one to 499 (e.g., from one to 399, from oneto 299, from one to 199, from one to 99, from one to 49, from one to 39,from one to 24). In certain embodiments, y is zero.

[0050] Examples of alkanoic acid esters include methyl3-hydroxybutyrate, ethyl 3-hydroxybutyrate, methyl 3-hydroxypropionate,ethyl 3-hydroxy propionate, methyl 4-hydroxybutyrate, ethyl4-hydroxybutyrate, cyclohexyl 3-hydroxybutyrate, cyclohexyl4-hydroxybutyrate, stearyl 4-hydroxybutyrate and stearyl3-hydroxybutyrate.

[0051] In some embodiments, an ester formed by treating a PHA is analkenoic acid ester. In certain embodiments, an alkenoic acid ester canbe represented by the structure:

[0052] Without wishing to be bound by theory, it is believed thatalkenoic acid esters can be formed, for example, in a dehydrationreaction that can occur prior or subsequent to alcoholysis of the PHA orPHA intermediate ester bond, resulting in formation of one or morecarbon-carbon double bonds. In certain embodiments (e.g., when n iszero), alkenoic acid esters are formed when one or more of R₁, R₂, R₃and R₄ (e.g., one or both of R₃ and R₄) is a hydrogen atom.

[0053] Examples of alkenoic acid esters include ethyl crotonate, methylcrotonate, butyl crotonate, 2-ethyl hexyl crotonate, ethyl 2-octenoateand ethyl 2 pentenoate.

[0054] As noted above, the ester is generally formed by combining thePHA with an alcohol, and exposing the PHA to elevated temperature and/orelevated pressure.

[0055] In general, the amount of alcohol used can be selected asdesired. In certain embodiments (e.g., when it is desirable to form anester for which y=0), at least about one mole (e.g., at least about twomoles, at least about four moles) of alcohol is used per mole of monomerunit in the PHA and/or at most about 20 moles (e.g., at most about 10moles, at most about six moles) of alcohol are used per mole of PHAmonomer unit. For example, from about two moles to about 20 moles (e.g.,from about two moles to about 10 moles) of alcohol can be used per moleof PHA monomer unit. In some embodiments (e.g., when it is desirable toform ester for which y>0), less than one mole (e.g., less than about 0.9mole, less than about 0.75 mole, less than about 0.5 moles) of alcoholis used per mole of monomer unit in the PHA.

[0056] The temperature can generally be selected as desired. Typically,the temperature greater than about 25° C. In some embodiments, thetemperature can be at least about 160° C. (e.g., at least about 170° C.,at least about 180° C.). In certain embodiments, the temperature can beat most about 220° C. (e.g., at most about 210° C., at most about 200°C.). For example, the temperature can be from about 160° C. to about220° C. (e.g., from about 170° C. to about 210° C., from about 170° C.to about 200° C.).

[0057] Generally, the pressure can be selected as desired. Typically,the pressure is greater than about 14 psig. In certain embodiments, thepressure can be at least about 50 psig (e.g., at least about 100 psig).In some embodiments, the pressure can be at most about 500 psig (e.g.,at most about 250 psig). For example, the pressure can be from about 50psig to about 500 psig. Typically, elevated pressure is achieved usingan inert gas (e.g., nitrogen, helium, argon, krypton, xenon, etc.).

[0058] In certain embodiments, the PHA can be treated while usingrelatively little solvent (e.g., relatively little halogenated solvent)other than the alcohol. For example, the total amount of solvent otherthan the alcohol present during the treatment of the PHA to form theester can be less than one milliliter (e.g., less than about 0.9milliliter, less than about 0.8 milliliter, less than about 0.7milliliter, less than about 0.6 milliliter, less than about 0.5milliliter, less than about 0.4 milliliter, less than about 0.3milliliter, less than about 0.2 milliliter, less than about 0.1milliliter, less than about 0.05 milliliter, about zero milliliter) pergram of PHA.

[0059] In certain embodiments, the amount of undesired byproducts isrelatively small. For example, in some embodiments it is desired to forman alkanoic acid ester, alkenoic byproducts can be undesired. In someembodiments, the percent yield of undesirable byproducts (e.g., alkenoicbyproducts) from the PHA is less than about 10% (e.g., less than abouteight percent, less than about five percent, less than about threepercent, less than about one percent).

[0060] In some embodiments, the PHA treatment to form the ester isperformed in the absence of a catalyst.

[0061] In certain embodiments, the PHA treatment to form the ester isperformed in the presence of an appropriate catalyst. In general, thecatalyst can be a protic catalyst or an aprotic catalyst. Examples ofprotic catalysts include sulfuric acid, para-toluene sulfonic acid,hydrochloric acid and phosphoric acid. Examples of aprotic catalystsinclude certain transesterification catalysts (e.g., metal-containingtransesterification catalysts), such as, tin compounds (e.g., dibutyltindilaurate, stannous oxide, dibutyl tin oxide, dibutyl tin chloride),titanium compounds (e.g., tetraalkoxy titanates, ethanolamine complexedwith titanium), zinc compounds (e.g., zinc acetate, zinc chloride) andclays (e.g. montmorillonite K10 clay). In some embodiments, more thanone catalyst is used.

[0062] Generally, in embodiments in which a catalyst is used, the amountof catalyst can be selected as desired. In some embodiments, thecatalyst can be at least about 0.1 weight percent (e.g., at least about0.25 weight percent, at least about 0.5 weight percent, at least aboutone weight percent) of the total amount of PHA present when the catalystis added. In certain embodiments, the catalyst can be at most about 10weight percent (e.g., at most about five weight percent, at most aboutthree weight percent) of the total amount of PHA present when thecatalyst is added. For example, the catalyst can be from about 0.1weight percent to about 10 weight percent (e.g., from about 0.25 weightpercent to about five weight percent of the total amount of PHA presentwhen the catalyst is added.

[0063] In some embodiments, while using a relatively small amount ofalcohol relative to PHA, an ester can be formed from the PHA at arelatively high percent yield. As an example, while using less thanabout 20 moles of alcohol per mole of PHA monomer repeat unit, thepercent yield of ester from the PHA is at least about 50% (e.g., atleast about 60%, at least about 70%, at least about 80%, at least about90%, at least about 95%, at least about 98%). As another example, whileusing less than about 10 moles of alcohol per mole of PHA monomer repeatunit, the percent yield of ester is at least about 50% (e.g., at leastabout 60%, at least about 70%, at least about 80%, at least about 90%,at least about 95%, at least about 98%). As a further example, whileusing less than about five moles of alcohol per mole of PHA monomerrepeat unit, the percent yield of ester from the PHA is at least about50% (e.g., at least about 60%, at least about 70%, at least about 80%,at least about 90%, at least about 95%, at least about 98%). As anadditional example, while using from about one mole of alcohol per moleof PHA monomer repeat unit to about five moles of alcohol per PHAmonomer repeat unit, the percent yield of ester from the PHA is at leastabout 50% (e.g., at least about 60%, at least about 70%, at least about80%, at least about 90%, at least about 95%, at least about 98%).

[0064] The methods can further include isolating at least a portion ofthe ester formed by treating the PHA. For example, in embodiments inwhich the PHA is derived from biomass and the PHA is not removed fromthe biomass before being treated to form the ester, the methods caninclude removing at least a portion (e.g., at least about 10 weightpercent, at least about 20 weight percent, at least about 30 weightpercent, at least about 40 weight percent, at least about 50 weightpercent, at least about 60 weight percent, at least about 70 weightpercent, at least about 80 weight percent, at least about 90 weightpercent, at least about 95 weight percent, at least about 98 weightpercent) of the ester from the biomass.

[0065] In embodiments in which the PHA is a PHA copolymer, multipleesters can be formed, corresponding to the different monomer units inthe PHA copolymer and the hydrocarbon unit in the alcohol. For example,the PHA can be poly 3-hydroxybutyrate-co-3-hydroxypropionate, thealcohol can be methanol, and the esters can be methyl 3-hydroxybutyrateand methyl 3-hydroxypropionate.

[0066] In embodiments in which a PHA homopolymer is combined withdifferent alcohols and treated as described above, multiple esters canbe formed, corresponding to the monomer unit contained in the PHAhomopolymer and the hydrocarbon units from the alcohols. For example,the PHA can be poly 3-hydroxybutyrate, the alcohols can be methanol andethanol, and the esters can be methyl 3-hydroxybutyrate and ethyl3-hydroxybutyrate.

[0067] In embodiments in which PHA copolymer is combined with differentalcohols, multiple esters can be formed, corresponding to the differentmonomer units in the PHA copolymer and the different hydrocarbon unitsin the alcohols. For example, the PHA can be poly3-hydroxybutyrate-co-3-hydroxypropionate, the alcohols can be methanoland ethanol, and the esters can be methyl 3-hydroxybutyrate, methyl3-hydroxypropionate, ethyl 3-hydroxybutyrate and ethyl3-hydroxypropionate.

[0068] The esters can be used in various applications. For example, anester can be used as a chiral synthetic building block (e.g., R-methyl3-hydroxy butyrate).

[0069] As another example, ethyl 3-hydroxybutyrate can be used as awater miscible biodegradable cleaning solvent (e.g., in inks and/orfluxes).

[0070] In some embodiments, an ester can serve as a solvent, such as acoalescing solvent (e.g., to promote film from latex compositions, suchas paints, which can contain an emulsion or suspension of polymerparticles in an aqueous medium). When present in a liquid mixture (e.g.,latex composition), the ester can form from about 0.05 weight percent toabout 25 weight percent of the mixture. An ester can, for example,reduce a glass transition temperature of composition during the dryingand film forming process. An ester can, for example, reduce the volatileorganic content in aqueous-based polymer compositions. The esters can,for example, reduce the film forming temperature of a composition. Anester can, for example, evaporate over time (e.g., within about fivedays) after film formation, and thereby be removed from the film afterformation. An ester can, for example, act as an adhesion promoter, andpromote the adhesion of solvent based inks (e.g., lithographic inks,gravure inks), solvent based paints or coatings, and/or epoxidebased-paints or coatings.

[0071] Amides

[0072] Treating a PHA to form an amide generally includes combining thePHA with an amine (e.g., a primary amine, a secondary amine), and usingelevated temperature and/or pressure.

[0073] In general, the amine can be selected as desired. In someembodiments, the amine is an aliphatic primary amine (e.g., an aliphaticprimary amine having up to 20 carbon atoms). In certain embodiments, theamine is an oxygen-containing amine (e.g., mono-ethanolamine,di-ethanolamine). In some embodiments, the amine is a diamine (e.g., anethylene diamine). In certain embodiments, the amine is a cyclic amine.In some embodiments, the amine can be represented by the structureR₈R₉NH, where each of R₈ and R₉ is independently a hydrogen atom or ahydrocarbon radical that contains one or more carbon atoms (e.g., onecarbon atom, two carbon atoms, three carbon atoms, four carbon atoms,five carbon atoms, six carbon atoms, seven carbon atoms, eight carbonatoms, etc.). A hydrocarbon radical can be saturated or unsaturated,substituted or unsubstituted, branched or straight chained, and/orcyclic or acyclic. Examples of substituted hydrocarbon radicals includehalo-substituted hydrocarbon radicals, hydroxy-substituted hydrocarbonradicals, nitrogen-substituted hydrocarbon radicals andoxygen-substituted hydrocarbon radicals. Examples of hydrocarbonradicals include methyl, ethyl, propyl, butyl, 2-ethylhexyl and2-hydroxyethyl.

[0074] Examples of amines include ammonia, methyl amine, ethyl amine,pyrrolidone, and 2-hydroxyethyl amine.

[0075] In certain embodiments, an amide formed by treating the PHA is analkanoic amide. In some embodiments, an alkanoic amide can berepresented by the structure:

[0076] Examples of alkanoic amides include N-methyl 3-hydroxybutyramide,N-ethyl 3-hydroxybutyramide, N-methyl 4-hydroxybutyramide, N-ethyl4-hydroxybutyramide, N-hydroxyethyl 4-hydroxybutyramide,6-hydroxyhexanamide.

[0077] In some embodiments, an amide formed by treating a PHA is analkenoic amide. In certain embodiments, an alkenoic amide can berepresented by the structure.

[0078] Without wishing to be bound by theory, it is believed thatalkenoic amides can be formed, for example, in an elimination reactionwhich can occur prior or subsequent to aminolysis of the PHA or PHAintermediate ester bond via reactions that involve dehydration,resulting in formation of one or more carbon-carbon double bonds. Incertain embodiments, alkenoic amides are formed when one or more of R₁,R₂, R₃ and R₄ (e.g., one or both of R₃ and R₄) is a hydrogen atom. Insome embodiments, alkenoic amides are formed when R₃ and/or R₄ is ahydrogen atom.

[0079] Examples of alkenoic amides include acrylamide andmethacrylamide.

[0080] As noted above, the amide is generally formed by combining thePHA with an amine, and exposing the PHA to elevated temperature and/orelevated pressure.

[0081] In general, the amount of amine used can be selected as desired.In certain embodiments (e.g., when it is desirable to form an amide forwhich y=0), at least about one mole (e.g., at least about 1.5 moles, atleast about two moles, at least about three moles) of amine is used permole of monomer unit in the PHA and/or at most about 20 moles (e.g., atmost about 10 moles, at most about five moles) of amine are used permole of PHA monomer unit. For example, from about 1.5 moles to about 20moles (e.g., from about 1.5 moles to about five moles) of amine can beused per mole of PHA monomer unit. In some embodiments (e.g., when it isdesirable to form amide for which y>0), less than one mole (e.g., lessthan about 0.9 mole, less than about 0.75 mole, less than about 0.5moles) of amine is used per mole of monomer unit in the PHA.

[0082] The temperature can generally be selected as desired. Typically,the temperature greater than about 25° C. (e.g., at least about 40° C.,at least about 50° C., at least about 60° C.). In some embodiments, thetemperature can be at most about 100° C. (e.g., at most about 90° C., atmost about 80° C.). For example, the temperature can be from about 40°C. to about 90° C. (e.g., from about 50° C. to about 90° C., from about60° C. to about 90° C.).

[0083] Generally, the pressure can be selected as desired. In someembodiments, the pressure is about 14 psig. In certain embodiment, thepressure is greater than about 14 psig (e.g., at least about 50 psig, atleast about 100 psig) and/or at most about 500 psig (e.g., at most about250 psig). For example, the pressure can be from about 50 psig to about500 psig. Typically, elevated pressure is achieved using nitrogen,although other gases, such as an inert gases, can be used (e.g., helium,argon, krypton, xenon, etc.).

[0084] In certain embodiments, the PHA can be treated while usingrelatively little solvent (e.g., relatively halogenated solvent) otherthan the amine. For example, the total amount of solvent other than themine present during the treatment of the PHA to form the amide can beless than one milliliter (e.g., less than about 0.9 milliliter, lessthan about 0.8 milliliter, less than about 0.7 milliliter, less thanabout 0.6 milliliter, less than about 0.5 milliliter, less than about0.4 milliliter, less than about 0.3 milliliter, less than about 0.2milliliter, less than about 0.1 milliliter, less than about 0.05milliliter, about zero milliliter) per gram of PHA.

[0085] In certain embodiments, the amount of undesired byproducts isrelatively low. For example, in some embodiments where alkanoic amidesare being prepared, it can be undesirable to form alkenoic byproducts.In some embodiments, the percent yield of undesirable byproducts (e.g.,alkenoic byproducts) from the PHA is less than about 10% (e.g., lessthan about eight percent, less than about five percent, less than aboutthree percent, less than about one percent).

[0086] In some embodiments, an amide can be formed from the PHA at arelatively high percent yield. For example, the percent yield of amidefrom the PHA can be at least about 50% (e.g., at least about 60%, atleast about 70%, at least about 80%, at least about 90%, at least about95%, at least about 98%).

[0087] In certain embodiments, an acyclic amide formed via the treatmentof a PHA can be further treated to form a cyclic amide (e.g., a lactam).In some embodiments, the cyclic amide has a ring with at least fourcarbon atoms (e.g., five carbon atoms, six carbon atoms, seven carbonatoms, eight carbon atoms, nine carbon atoms, ten carbon atoms. In someembodiments, a cyclic amide has the following structure:

[0088] As an example, N-methylpyrrolidone can be formed from N-methyl4-hydroxybutyramide (e.g., N-methyl 4-hydroxybutyramide formed bytreating poly 4-hydroxybutyrate and methylamine). As another example,N-ethylpyrrolidone can be formed from N-ethyl 4-hydroxybutyramide (e.g.,ethyl 4-hydroxybutyramide formed by treating formed by treating poly4-hydroxybutyrate and ethylamine). As another example,N-hydroxyethylpyrrolidone can be formed from N-ethyl 4-hydroxybutyramide(e.g., N-hydroxyethyl 4-hydroxybutyramide formed by treating poly4-hydroxybutyrate and hydroxyethylamine).

[0089] In general, forming a cyclic amide from an acyclic amide includesheating the acyclic amide to a temperature of at least about 100° C.(e.g., at least about 200° C., at least about 250° C., at least about275° C.) at a pressure of at least about 50 psig (at least about 100psig, at least about 250 psig, at least about 500 psig) of nitrogen orone or more other gases (e.g., an inert gas, such as helium, argon,krypton, xenon, etc.).

[0090] In some embodiments, the percent yield of cyclic amide fromacyclic amide is at least about 50% (e.g., at least about 60%, at leastabout 70%, at least about 80%, at least about 90%, at least about 95%,at least about 98%). In certain embodiments, the percent yield of cyclicamide from the PHA is at least about 50% (e.g., at least about 60%, atleast about 70%, at least about 80%, at least about 90%, at least about95%, at least about 98%).

[0091] In some embodiments in which the PHA is derived from biomass,most of the acyclic amide that is formed from the PHA is not removedfrom the biomass before being treated to form the cyclic amide. Forexample, in certain embodiments, less than about 50 weight percent(e.g., less than about 40 weight percent, less than about 30 weightpercent, less than about 20 weight percent, less than about 10 weightpercent, less than about weight percent five weight percent, less thanabout three weight percent, less than about one weight percent, aboutzero weight percent) of the acyclic amide that is treated to form thecyclic amide is removed from the biomass before being treated to formthe cyclic amide.

[0092] The methods can further include isolating at least a portion ofthe amide formed by treating the PHA. For example, in embodiments inwhich the PHA is derived from biomass and the PHA is not removed fromthe biomass before being treated to form the amide, the methods caninclude removing at least a portion (e.g., at least about 10 weightpercent, at least about 20 weight percent, at least about 30 weightpercent, at least about 40 weight percent, at least about 50 weightpercent, at least about 60 weight percent, at least about 70 weightpercent, at least about 80 weight percent, at least about 90 weightpercent, at least about 95 weight percent, at least about 98 weightpercent) of the amide from the biomass.

[0093] In embodiments in which the PHA is a PHA copolymer, multipleamides can be formed, corresponding to the monomer unit in the PHAcopolymers and the amine. For example, the PHA can be poly3-hydroxybutyrate-co-3-hydroxypropionate, the amine can be methylamine,and the amides can be N-methyl 3-hydroxybutyramide and N-methyl3-hydroxypropionamide.

[0094] In embodiments in which a PHA homopolymer is combined withdifferent amines and treated as described above to form amides,multiples amides can be formed, corresponding to the monomer unitcontained in the PHA homopolymer and the amines. For example, the PHAcan be poly 3-hydroxybutyrate, the amines can be methylamine andethylamine, and the amides can be N-methyl 3-hydroxybutyramide andN-ethyl 3-hydroxybutyramide.

[0095] In embodiments in which the PHA is a PHA copolymer and multipleamines are used, multiple amides can be formed, corresponding to thedifferent monomer units in the copolymer and the different amines. Forexample, the PHA can be poly 3-hydroxybutyrate-co-3-hydroxypropionate,the amines can be methylamine and ethylamine, and the amides can beN-methyl 3-hydroxybutyramide, N-methyl 3-hydroxypropionamide, N-ethyl3-hydroxybutyramide and N-ethyl 3-hydroxypropionamide.

[0096] The amides can be used in a variety of applications. For example,N-hydroxyethyl pyrrolidone can be used to produce N-vinyl pyrrolidone,which, in turn, can be used to produce polyvinylpyrrolidone, which canbe used, for example, in adhesive applications, as a thickener, and/oras a flocculent. As another example, 3-hydroxypropanamide can be used toproduce acrylamide, which, in turn, can be used to producepolyacrylamide, which can be used, for example, in a compositioncontaining moisture absorbing polymers. As a further example, N-methylpyrrolidone can be used as a carrier solvent for paint, ink, adhesiveformulations, as a cleaning/degreasing solvent, and/or as a component inpaint stripper formulations.

[0097] Diols

[0098] In general, treating a PHA to form a diol includeshydrogenolyzing the PHA. Typically, this includes heating the PHA in thepresence of a reducing species (e.g., reducing agent). Optionally, thiscan be done in the presence of a solvent and/or a catalyst. In someembodiments, elevated pressure is used (e.g., elevated pressure ofhydrogen gas).

[0099] Typically, the PHA is heated to a temperature of at least about100° C. (e.g., at least about 150° C., at least about 160° C.). In someembodiments, the temperature is at most about 260° C. (e.g., at mostabout 230° C.). For example, the temperature can be from about 100° C.to about 260° C. (e.g., from about 130° C. to about 230° C., from about160° C. to about 230° C.).

[0100] In certain embodiments, a diol formed by treating a PHA has thestructure:

[0101] Examples of diols include 1,4-butanediol, 1,3-propanediol,1,3-butanediol, 1,6-hexanediol, 1,3-pentanediol, 1,3-hexanediol,1,3-octanediol, 1,2-propanediol, ethylene glycol and propylene glycol.

[0102] In embodiments in which a solvent is used, the solvent cangenerally be selected as desired. In some embodiments, the solvent is analcohol. Examples of alcohols include C₁-C₄ alcohols, such as methanol,ethanol, propanol and butanol. In some embodiments, an alcohol solventcan be the same as the diol being formed by treating the PHA.

[0103] In embodiments in which a solvent is used, the concentration ofPHA in the solvent is at least about five weight percent (e.g., at leastabout 10 weight percent). In some embodiments, the concentration of PHAin the solvent is at most about 90 weight percent (e.g., at most about50 weight percent). For example, the concentration of PHA in the solventcan be from about five weight percent to about 90 weight percent (e.g.,from about five weight percent to about 90 weight percent).

[0104] In certain embodiments, the PHA can be treated while usingrelatively little solvent (e.g., relatively little halogenated solvent)other than the alcohol. For example, the total amount of solvent otherthan the alcohol present during the treatment of the PHA to form theester can be less than one milliliter (e.g., less than about 0.9milliliter, less than about 0.8 milliliter, less than about 0.7milliliter, less than about 0.6 milliliter, less than about 0.5milliliter, less than about 0.4 milliliter, less than about 0.3milliliter, less than about 0.2 milliliter, less than about 0.1milliliter, less than about 0.05 milliliter, about zero milliliter) pergram of PHA.

[0105] Generally, in embodiments in which hydrogen is used as thereducing species, elevated pressure is used. In some embodiments, thepressure (e.g., hydrogen pressure) used is at least about 200 psig(e.g., at least about 500 psig, at least about 1000 psig, at least about2500 psig, at least about 3000 psig). In certain embodiments, thepressure (e.g., hydrogen pressure) is at most about 5000 psig (e.g., atmost about 4000 psig). Other gases (e.g., nitrogen) may be used inaddition to hydrogen.

[0106] In embodiments in which the PHA treatment to form the diol isperformed in the presence of a catalyst, the catalyst is typically ametal catalyst. Examples of catalysts include copper chromite catalysts,platinum catalysts, (e.g., 2,4-Pentanedionate Platinum (II),Dichloro(norbornadiene)platinum (II)), palladium catalysts (e.g.,Palladium (II) Acetate Trimer, Tris(dibenzylideneacetone)dipalladium(0),trans-Dichlorobis(triphenylphosphine)palladium (II)), nickel complexes,rainey nickel, ruthinium catalysts (e.g., ruthinium dichloridebis-(triphenylphosphine)(1,2-ethanediamine), ruthinium dichloridebis-(tri-p-tolylphosphine)(1,2-ethanediamine)), cobalt, rhodiumcatalysts (e.g., 2,4-Pentanedionate rhodium, Rhodium (III),Chloro(norbornanediene)rhodium (I) Dimer, Rhodium (II) Octanoate Dimer),Iridium catalysts (e.g., 2,4-Pentanedionate Iridium (III) andHydridocarbonyltris(triphenylphosphine)iridium (I)).

[0107] Generally, in embodiments in which a catalyst is used, the amountof catalyst can be selected as desired. In some embodiments, thecatalyst can be at least about 0.1 weight percent (e.g., at least about0.25 weight percent, at least about 0.5 weight percent, at least aboutone weight percent) of the total amount of PHA present when the catalystis added. In certain embodiments, the catalyst can be at most about 10weight percent (e.g., at most about five weight percent, at most aboutthree weight percent) of the total the total amount of PHA present whenthe catalyst is added. For example, the catalyst can be from about 0.1weight percent to about 10 weight percent (e.g., from about 0.25 weightpercent to about five weight percent of the total the total amount ofPHA present when the catalyst is added.

[0108] In embodiments in which the PHA treatment to form the diol isperformed in the presence of a reducing agent, the reducing agent can bean active metal hydride. Examples of reducing agents include lithiumaluminum hydride, sodium aluminum hydride, sodium borohydride andVitride (Zealand Chemicals).

[0109] In general, at least about two (e.g., at least about 2.5, atleast about three) equivalents of reducing agent are used per mole ofPHA monomer unit converted to diol.

[0110] In certain embodiments, the amount of undesired byproducts isrelatively small. For example, alkenoic byproducts can be undesired. Insome embodiments, the percent yield of undesirable byproducts (e.g.,alkenoic byproducts) from the PHA is less than about 10% (e.g., lessthan about eight percent, less than about five percent, less than aboutthree percent, less than about one percent).

[0111] In some embodiments, the methods result in a relatively highyield of the diol. For example, the percent yield of the diol from thePHA can be at least about 30% (e.g., at least about 35%, at least about40%, at least about 45%, at least about 50%, at least about 55%, atleast about 60%, at least about 65%, at least about 70%, at least about75%, at least about 80%, at least about 85%, at least about 90%, atleast about 95%, at least about 98%).

[0112] In embodiments in which the PHA is a chiral PHA, the diol can bea chiral diol, and the percent chirality yield of chiral diol can berelatively high. For example, the percent chirality yield of a chiraldiol from a chiral PHA can be at least about five percent (e.g., atleast about 10%, at least about 25%, at least about 50%, at least about75%, at least about 85%, at least about 90%, at least about 95%, atleast about 98%).

[0113] The diols can be used in a variety of applications. As anexample, a diol can be used in aromatic polyester production. As anotherexample, chiral diols (e.g., the D-isomer of 1,3-butanediol from poly3-hydroxybutyrate) can be used in pharmaceutical derivatives and/ornutraceutical derivatives (e.g., via the reaction of chiral1,3-butanediol with chiral D-3-hydroxybutyrate and/or acetoacetate toprovide a chiral ester). As a further example, 1,4-butanediol (e.g.,from poly 4-hydroxybutyrate) can be useful in the production of aromaticpolyesters, tetrahydrofuran, gamma butyrolactone, aliphatic polyesters,urethanes and elastomers. As an additional example, 1,6-hexane diol(e.g., from poly 6-hydroxyhexanoate) is commonly used in polyurethanesand polyester resins. 1,3-butanediol, 1,3-pentanediol and/or1,3-hexanediol can also be combined with diacids (e.g., adipic acid,terephthalic acid, succinic anhydride) to form polyester resins.

[0114] Alkenoic Acids

[0115] In general, treating a PHA to form an alkenoic acid (e.g., a1,2-unsaturated acid, a 2,3-unsaturated acid) includes heating the PHA.

[0116] Typically, the PHA is heated to a temperature of at least about100° C. (e.g., at least about 150° C., at least about 200° C., at leastabout 250° C.). In certain embodiments, the PHA is heated to atemperature of at most about 300° C.

[0117] Generally, the pressure used when heating the PHA can be selectedas desired. As an example, the PHA can be heated at atmospheric pressure(e.g., while exposed to air or inert gas). As another example, the PHAcan be heated at elevated pressure.

[0118] In certain embodiments, an alkenoic acid formed by treating a PHAhas the structure:

[0119] Examples of alkenoic acids include acrylic acid, crotonic acid,pentenoic acid, octenoic acid, ethyl crotonate, methyl crotonate, butylcrotonate, 2-ethylhexyl crotonate, ethyl 2-octenoate, ethyl 2pentenoate, ethyl 2-decanoate and vinyl acetic acid.

[0120] In certain embodiments, the PHA can be treated while usingrelatively little or no solvent (e.g., relatively little halogenatedsolvent). For example, the total amount of solvent present during thetreatment of the PHA to form the alkenoic acid can be less than onemilliliter (e.g., less than about 0.9 milliliter, less than about 0.8milliliter, less than about 0.7 milliliter, less than about 0.6milliliter, less than about 0.5 milliliter, less than about 0.4milliliter, less than about 0.3 milliliter, less than about 0.2milliliter, less than about 0.1 milliliter, less than about 0.05milliliter, about zero milliliter) per gram of PHA.

[0121] In some embodiments, an alkenoic acid can be formed from the PHAat a relatively high percent yield. For example, the percent yield ofalkenoic acid from the PHA can be at least about 50% (e.g., at leastabout 60%, at least about 70%, at least about 80%, at least about 90%,at least about 95%, at least about 98%). In some embodiments, thesepercent yields of alkenoic acid are achieved using PHA derived frombiomass when less than about 50 weight percent (e.g., less than about 40weight percent, less than about 30 weight percent, less than about 20weight percent, less than about 10 weight percent, less than aboutweight percent five weight percent, less than about three weightpercent, less than about one weight percent, about zero weight percent)of the PHA that is treated to form the alkenoic acid is removed from thebiomass before being treated to form the alkenoic acid.

[0122] The methods can further include isolating at least a portion ofthe alkenoic acid formed by treating the PHA. For example, inembodiments in which the PHA is derived from biomass and the PHA is notremoved from the biomass before being treated to form the amide, themethods can include removing at least a portion (e.g., at least about 10weight percent, at least about 20 weight percent, at least about 30weight percent, at least about 40 weight percent, at least about 50weight percent, at least about 60 weight percent, at least about 70weight percent, at least about 80 weight percent, at least about 90weight percent, at least about 95 weight percent, at least about 98weight percent) of the alkenoic acid from the biomass. In someembodiments, the temperatures used (e.g., at least about 200° C.)volatilize the alkenoic acid.

[0123] In embodiments where the PHA is a copolymer, different alkenoicacids can be formed corresponding to the different monomer units in thePHA copolymer. As an example, the PHA can be poly3-hydroxybutyrate-co-3-hydroxyvalerate, and the alkenoic acids can becrotonic acid, pentenoic acid, 2-pentenoic acid, 2-butenoic acid and/or2 octenoic acid.

[0124] The alkenoic acids can be used in various applications.

[0125] In some embodiments, an alkenoic acid can be used in apolymerization process (e.g., a free radical polymerization process) toform a useful material. As an example, crotonic acid can be used in afree radical polymerization process to form a vinyl acetate-crotonatecopolymer for use in hair spray formulations. As another example,acrylic acid can be used within polymerization processes to producepolyacrylate resins for use in paints, adhesives, coatings, thickeners(e.g., aqueous thickeners), resins (e.g., thermoplastic resins) andmodifiers (e.g., impact modifiers).

[0126] The following examples are illustrative and not intended aslimiting.

EXAMPLE 1

[0127] Ethyl-3-hydroxybutyrate was prepared from a PHA (poly3-hydroxybutyrate) as follows. A solution of 1.0 g of poly3-hydroxybutyrate (94% purity) in 4.0 ml of absolute ethanol wasprepared in a glass pressure bottle. The PHA was derived from biomass.10.5 mg of di-butyl tin oxide and 0.5 ml of diphenylmethane were addedas a catalyst and as an internal gas chromatographic standard,respectively. The mixture was heated to 180° C. with magnetic stirring.After 2.0 hours the percent yield of ethyl-hydroxybutyrate from the PHAwas 77.8%, and after 4.0 hours the percent yield ofethyl-hydroxybutyrate from the PHA was 92%.

EXAMPLE 2

[0128] Example 1 was repeated at 200° C., and after two hours ofreaction time the percent yield of ethyl-3-hydroxybutyrate from the PHAwas 82.2%.

EXAMPLE 3

[0129] Example 2 was repeated except that 10.5 mg of titaniumtetra-isopropoxide was used as the catalyst. After two hours of reactiontime, the percent yield of ethyl-3-hydroxybutyrate from PHA was 82.2%.

EXAMPLE 4

[0130] N-methyl 4-hydroxybutyramide was prepared by treating a PHA (poly4-hydroxybutyrate) as follows. A 300 ml 316 stainless steel autoclaveequipped with a stirrer, a gas inlet line, a vent line and a rupturedisc was charged with 13.1 g of poly 4-hydroxybutyrate and 20 g ofmethylamine. The PHA had been isolated from biomass. The autoclave was:flushed with nitrogen; put under 100 psig of nitrogen; heated withstirring to 80° C.; and held at this temperature for 5.0 hours. Theautoclave was then cooled to room temperature, vented and opened. ThePHA was completely consumed. The excess methylamine was removed under anitrogen stream, and the remaining dark brown liquid analyzed via gaschromatography (GC). The GC trace on a boiling point column showed onlyone component, and that point corresponded to N-methyl4-hydroxybutyramide.

EXAMPLE 5

[0131] N-Methylpyrrolidone was prepared as follows. The liquid fromExample 4 was heated under nitrogen with stirring in the same autoclaveto 280° C. and held at that temperature for two hours. The pressure was600 psig. After cooling, the clave was opened and the liquid contentsdischarged and analyzed via GC. The majority of the liquid wasmethylpyrrolidone, and the remainder of the liquid was unreacted amidehaving the same retention time as the starting amide. At 100% polymerconversion, the percent yield of methylpyrrolidone from PHA was inexcess of 90%.

EXAMPLE 6

[0132] 1,4-Butanediol was prepared from a PHA (poly 4-hydroxybutyrate)as follows. A one liter autoclave was charged with 40 g of poly4-hydroxybutyrate, 400g of methanol and 5.0 g of powdered bariumpromoted copper chromite obtained from Engelhard. The PHA had beenisolated from biomass. The clave was pressured with hydrogen to 200 psigand the pressure was released. This was done four times and the clavethen pressured to 2000 psig with hydrogen. The clave was then heatedwith stirring to 160° C. and the final pressure adjusted to 3500 psigwith hydrogen. The clave was kept at 160° C. for 2.0 hours, and thetemperature then raised to 180° C. for an additional 2.0 hours. Thepressure was adjusted to 3500 psig. Finally, the temperature was raisedto 200° C. for an additional 2.0 hours, again at 3500 psig hydrogen. Theclave was then cooled to room temperature and vented. Any remaininghydrogen was purged with nitrogen and the contents discharged. There wasno solid PHA left, and the solution was water white. Analysis of thesolution by GC after filtering off the catalyst showed that the majorproduct was 1,4-butanediol.

EXAMPLE 7

[0133] Crotonic acid was prepared from a PHA (poly 3-hydroxybutyrate) asfollows. Seven grams of biomass (with most water removed, butnon-lyophilized) from the fermentation process of poly 3-hydroxybutyrate(comprising 4.3 g poly 3-hydroxybutyrate having a molecularweight>700,000, 2.1 g of cell components and 0.6 g of inorganic saltsremaining from the fermentation media) was heated at 245° C. in an airatmosphere. After 30 minutes, no further volatile components wereobserved. The volatile component was analyzed by GC. The yield ofalkenoic acid component was 98.0% based on the poly 3-hydroxybutyratecomponent of the biomass. The composition of the alkenoic acid fractionwas 96% crotonic acid, and no unsaturated dimer or trimer was detected.

EXAMPLE 8

[0134] Crotonic acid was prepared from a PHA (poly 3-hydroxybutyrate) asfollows. Eight grams of biomass (with most water removed, butnon-lyophilized) from the fermentation process of poly 3-hydroxybutyratewashed free of soluble inorganic salts (comprising 5.7 g poly3-hydroxybutyrate having a molecular weight>700,000, 2.3 g of cellcomponents) was heated at 245° C. in an air atmosphere. After 30 minutesno further volatile components were observed. The volatile component wasanalyzed by GC. The yield of the alkenoic acid component was 96.8.0%based on the poly 3-hydroxybutyrate component of the biomass. Thecomposition of alkenoic acid fraction: 95.5% crotonic acid, and nounsaturated dimer or trimer was detected.

EXAMPLE 9

[0135] 2-ethylhexyl R-3-hydroxybutyrate was prepared from a PHA (ethylR-3-hydroxybutyrate) as follows. 132 g of ethyl R-3-hydroxybutyrate werecombined with 130 g of 2-ethylhexanol and 0.5 g of sulfuric acidcatalyst. The mixture was heated to a temperature of 140° C. for 2hours, and the ethanol removed by fractional distillation. Gaschromatography (GC) identified the resultant product as being 98% pure2-ethylhexyl R-3-hydroxybutyrate with the following properties: boilingpoint at atmospheric pressure: 495-502° F.; flash point (closed cup):260° F.; kinematic viscosity: 11.06 cSt; and relative evaporation rate:<0.01 (butyl acetate=1).

EXAMPLE 10

[0136] Cyclohexyl R-3-hydroxybutyrate was prepared from a PHA(poly-R-3-hydroxybutyrate) as follows. 900 mL of cyclohexanol, 200 gramsof poly-R-3-hydroxybutyrate and 5.26 grams of dibutyl-tin oxide werereacted at 142-147° C. for 8 hours. The crude brown product was filteredand short-path distilled. The first distillate was 560 mL of purecyclohexanol. The second distillate was clear cyclohexyl ester withpurity by GC of 97.6% and had the following physical properties: boilingpoint at atmospheric pressure: 485-502° F.; flash point (closed cup):255° F.; kinematic viscosity: 28.87 cSt; relative evaporation rate:<0.01 (butyl acetate=1).

EXAMPLE 11

[0137] 4-methylcyclohexyl R-3-hydroxybutyrate was prepared frompoly-R-3-hydroxybutyrate as follows. 900 mL of methylcyclohexanol, 200grams of poly-R-3-hydroxybutyrate and 5.26 grams of dibutyl-tin oxidewere reacted at 142-147° C. for 8 hours. The crude brown product wasfiltered and short-path distilled. The first distillate was 560 mL ofpure methylcyclohexanol. The second distillate was clearmethylcyclohexyl ester with purity by GC of 97.6% and had the followingphysical properties: boiling point at atmospheric pressure: 459-485° F.;flash point (closed cup): 262° F.; kinematic viscosity: 30.49 cSt; andrelative evaporation rate: <0.01 (butyl acetate=1).

Evaluation of Examples 9 Through 11 In Coating Systems

[0138] The following evaluation was performed independently for each ofthe solvents prepared in Examples 9-11. The solvent was slowly added to50 g of emulsion under continuous stirring for at least 10 minutes. Thestability of the system was determined by allowing the emulsion to standfor 24 hours and the consistency visually determined to see if any phaseseparation or gel formation had developed.

[0139] The glass transition temperature (Tg) for the polymer, and theblends was determined by placing a small sample of the emulsion onto aglass plate and allowing the water to evaporate. The dried material wasthen transferred to a Perkin Elmer DSC and heated from −50° C. to +100°C. at 10° C./minute. The mid point glass transition temperature wasdetermined from the inflection in the heat capacity versus temperaturecurve.

[0140] Film forming properties were determined by storing the emulsionin a refrigerator at 5° C. overnight with a number of clean glassplates. A wet polymer film approximately 100-200 microns in thicknesswas applied to the glass plates which were then stored again in therefrigerator for several days. After this time period, the films wereexamined for integrity and strength. phr on dry Film forming Polymergrade solvent polymer stability Tg (C) properties 5C Airflex 30 NoneNone stable +32 No film, Polyvinyl powdery acetate Ex. 9 3.2 stable −5.2Tough clear film Ex. 9 6.8 stable −11.1 Tough clear film Ex. 10 3.2stable −4.6 Tough clear film Ex. 11 3.5 stable −4.9 Tough clear filmAirflex 4514 None None stable 69.4 No film, Polyvinyl powdery chlorideEx. 9 3.2 stable 10.2 No film, powdery Ex. 9 7.2 stable −7.2 Tough clearfilm Ex. 9 14.8  stable −15.2 Tough clear film Nacrylic 2500 None Nonestable 24 No film, Acrylic powdery copolymer Ex. 9 7.2 stable −5.2 Toughclear film Ex. 9 14.4  stable −24.4 Tough clear film Nacrylic 6408 NoneNone stable 52 No film, Acrylic powdery copolymer Ex. 9 8.6 stable 2.3Tough slightly opaque film Ex. 9 14.4  stable −24.3 Tough clear film

[0141] Other embodiments are in the claims.

1. A method, comprising: hydrogenolyzing a PHA to form a diol.
 2. Themethod of claim 1, wherein the PHA is hydrogenolyzed at a temperature ofat least about 100° C.
 3. The method of claim 1, wherein the percentyield of diol from the PHA is at least about five percent.
 4. The methodof claim 1, wherein the PHA is a chiral PHA, and a percent chiralityyield of chiral diol is at least about five percent.
 5. The method ofclaim 1, wherein hydrogenolysis occurs in the presence of ahydrogen-containing gas.
 6. The method of claim 5, wherein thehydrogen-containing gas comprises hydrogen gas.
 7. The method of claim1, wherein the PHA is derived from a biomass.
 8. The method of claim 7,wherein the biomass is selected from the group consisting of plantbiomass and microbial biomass.
 9. The method of claim 7, wherein thebiomass is non-lyophilized.
 10. The method of claim 7, wherein less thanabout 50 weight percent of the PHA that is treated to form the diol isremoved from the biomass before being treated to form the diol.
 11. Themethod of claim 1, further comprising contacting the PHA with a reducingagent during hydrogenolysis.
 12. The method of claim 1, furthercomprising contacting the PHA with a catalyst during hydrogenolysis. 13.The method of claim 1, further comprising combining the PHA with asolvent.
 14. The method of claim 1, wherein the diol has the structure:

and wherein n is selected from the group consisting of zero and aninteger greater than zero, and each of R₁, R₂, R₃, R₄, R₅ and R₆ isindependently selected from the group consisting of a hydrogen atom, ahalogen atom and a hydrocarbon radical.
 15. The method of claim 14,wherein n is zero, one or two.
 16. The method of claim 15, wherein R₂,R₃ and R₄ are each hydrogen atoms.
 17. The method of claim 16, whereinR₁ is selected from the group consisting of a hydrogen atom, a methylradical, an ethyl radical, a propyl radical, a butyl radical and apentyl radical.
 18. The method of claim 1, wherein the PHA is selectedfrom the group consisting of poly 3-hydroxybutyrate, poly3-hydroxypropionate, poly 4-hydroxybutyrate, poly 5-hydroxypentanoateand poly 6-hydroxyhexanoate.
 19. The method of claim 1, wherein the diolis selected from the group consisting of 1,4-butanediol,1,3-propanediol, 1,3-butanediol, 1,6-hexanediol, 1,3-pentanediol,1,3-hexanediol, 1,3-octanediol and 1,2-propanediol.
 20. The method ofclaim 1, wherein the PHA is contacted with the transition metal catalystin the substantial absence of a halogenated solvent.
 21. The method ofclaim 1, wherein the diol is formed without first forming a hydroxyacid.
 22. The method of claim 1, wherein the diol contains only onemonomer unit from the PHA.
 23. The method of claim 13, wherein thesolvent comprises an alcohol.
 24. The method of claim 23, wherein thealcohol comprises a diol.
 25. The method of claim 24, wherein the diolcomprises the same diol as formed by treating the PHA.
 26. The method ofclaim 24, further comprising reacting the diol to form a cyclic ether.27. The method of claim 26, wherein the cyclic ether comprises polyetherpolyol.
 28. The method of claim 1, wherein the PHA comprises a monomerunit selected from the group consisting of 3-hydroxybutyrate,3-hydroxypropionate, 4-hydroxybutyrate, 5-hydroxypentanoate and6-hydroxyhexanoate.
 29. A method, comprising: treating a biomasscontaining a PHA to form a PHA intermediate; and removing at least about10 weight percent of the PHA intermediate from the biomass.
 30. Themethod of claim 29, wherein at least about 20 weight percent of theintermediate is removed from the biomass.
 31. The method of claim 29,wherein at least about 30 weight percent of the PHA intermediate isremoved from the biomass.
 32. The method of claim 29, wherein at leastabout 40 weight percent of the PHA intermediate is removed from thebiomass.
 33. The method of claim 29, wherein, before treating the PHA,the biomass is non-lyophilized.
 34. The method of claim 29, wherein thebiomass is selected from the group consisting of plant biomass andmicrobial biomass.
 35. The method of claim 29, wherein less than about50 weight percent of the PHA that is treated to form the ester isremoved from the biomass before being treated to form the ester.
 36. Themethod of claim 29, further comprising, before treating the PHA to formthe ester, removing at least about 60 weight percent of the PHA that istreated to form the ester from the biomass.
 37. The method of claim 29,wherein the PHA intermediate contains at most 50 monomer units from thePHA.
 38. The method of claim 29, wherein the PHA intermediate containsonly one monomer unit from the PHA.
 39. The method of claim 29, whereinthe intermediate is selected from the group consisting of esters,amides, diols and alkenoic acids.
 40. The method of claim 29, whereinthe PHA is a chiral PHA, and a percent chirality yield of chiral PHAintermediate is at least about five percent.
 41. The method of claim 29,wherein the percent yield of alkenoic byproducts is less than about 10%.42. The method of claim 29, wherein the PHA is selected from the groupconsisting of poly 3-hydroxybutyrate, poly 3-hydroxypropionate, poly4-hydroxybutyrate, poly 5-hydroxypentanoate and poly 6-hydroxyhexanoate.43. The method of claim 29, wherein the PHA is a copolymer, and themethod forms multiple PHA intermediates.
 44. The method of claim 29,wherein treating the PHA includes heating the PHA to a temperature of atleast about 100° C.
 45. The method of claim 29, wherein the PHA iscombined with a solvent.
 46. The method of claim 29, wherein treatingthe PHA is performed at a pressure of at least about 50 psig.
 47. Themethod of claim 29, wherein treating the PHA occurs in a combinationthat contains less than about one milliliter of solvent other than thealcohol per gram of the PHA.
 48. The method of claim 29, wherein the PHAcomprises a monomer unit selected from the group consisting of3-hydroxybutyrate, 3-hydroxypropionate, 4-hydroxybutyrate,5-hydroxypentanoate and 6-hydroxyhexanoate.